title: Blood lactate threshold differences between arterialized and venous blood.
abstract: The purpose of this study was to investigate the differences between lactate thresholds determined from venous and arterialized blood. Seven endurance-trained college males performed an incremental bicycle ergometer exercise test until exhaustion. At the end of each 3 min stage, blood was sampled simultaneously from a hyperemized ear-lobe and an antecubital vein for the measurement of blood lactate (La-). Two-minute rest intervals separated each stage. Arterialized blood La-concentrations ([La-]) were significantly higher than venous blood at 350 W (14.5 and 9.7 mmol.l-1), maximal exercise (15.5 and 11.39 mmol.l-1), and throughout recovery. Arterialized [La-] was significantly higher than venous blood at the onset of blood La- accumulation (OBLA) (4.0 and 2.8 +/- 0.1 mmol.l-1), the individual anaerobic threshold (IAT) (3.4 +/- 0.3 and 2.1 +/- 0.1 mmol.l-1), and the ventilatory threshold (VT) (4.7 +/- 0.9 and 3.2 +/- 0.6 mmol.l-1). No significant differences were found between either La-threshold for arterialized or venous blood. The oxygen consumption (VO2) at OBLA was significantly lower when determined from arterialized blood La (2.3 +/- 0.2 and 2.8 +/- 0.2 l.min-1). No significant differences existed between the LT, OBLA, and IAT threshold-VO2 determinations from arterialized blood; however, significant differences were found between IAT-OBLA (2.1 +/- 0.2 and 2.8 +/- 0.2 l.min-1) and LT (2.2 +/- 0.2 l.min-1)-OBLA from venous blood. These results indicate that differences between venous and arterialized blood [La-] need to be considered when comparing different anaerobic threshold determinations.
authors.affiliation: Human Performance Laboratory, Ball State University, Muncie, Indiana 47306.
authors.forename: R A
authors.initials: RA
authors.lastname: Robergs
authors.forename: J
authors.initials: J
authors.lastname: Chwalbinska-Moneta
authors.forename: J B
authors.initials: JB
authors.lastname: Mitchell
authors.forename: D D
authors.initials: DD
authors.lastname: Pascoe
authors.forename: J
authors.initials: J
authors.lastname: Houmard
authors.forename: D L
authors.initials: DL
authors.lastname: Costill
mesh_terms: D000328:Adult; D015308:Anaerobic Threshold / Q000502:physiology*; D002196:Capillaries / Q000378:metabolism*; D004734:Energy Metabolism / Q000502:physiology; D015444:Exercise / Q000502:physiology*; D005080:Exercise Test; D006801:Humans; D007773:Lactates / Q000097:blood*; D019344:Lactic Acid; D008297:Male; D010807:Physical Endurance / Q000502:physiology; D012044:Regression Analysis; D014680:Veins / Q000378:metabolism*
chemical_list: D007773:Lactates; D019344:Lactic Acid